The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
Modern multiple speed automatic transmissions commonly employ a plurality of planetary gear sets having sun gears, planet gear carriers and ring gears which are permanently coupled together or selectively interconnected by clutches or grounded by brakes to achieve reverse gear and a plurality of forward gear ratios.
While the foregoing described components provide the fundamental and necessary reverse and forward speeds or gear ratios, automatic transmissions must also include control devices and components which select the desired or required gear ratio and facilitate shifts, both when the vehicle speed is increasing (upshifts) and when the vehicle speed is decreasing (downshifts).
A downshift may be required and may occur during two primary operating conditions: when the driver signals the engine and control components that rapid acceleration is desired, for example, in a passing situation, by fully depressing the accelerator pedal and when the vehicle is coasting and decelerating. In the former condition, there is invariably sufficient data available upon which the control components will base a decision to command a downshift. In the latter condition, however, the data will be more subtle and the decision to downshift as well as the transmission components which affect the downshift must operate smoothly and with a minimum of torque flow disruption.
The present invention is directed to a one way clutch and synchronizer having particular applicability to automatic transmissions which provides smooth and improved downshifts during periods of vehicle coasting and deceleration.